1. Field of the Invention
The present invention relates to a vehicle and suspension system with an automatically locking front floating axle that locks when it detects that one of the rear wheels is unweighted and is directed to a control system for such a suspension.
2. Description of the Prior Art
Wheeled vehicles that operate on a slope and especially those that work on side slopes may require adjustable suspensions that reposition the vehicle frame with respect to the ground to maintain a level orientation. Such systems provide height adjustment while increasing stability and maintaining the vehicle at a substantially level operating orientation. Many types of agricultural vehicles such as over the row harvesters with a relatively high center of gravity require such adjustable suspension systems.
Systems are known that utilize hydraulic cylinders to maintain the vehicle at a level orientation for improved positioning relative to plants being treated or harvested. Typical prior art systems may have front and rear hydraulic cylinders that are interconnected to form a master/slave system. Systems are known that use interconnected front wheels or rear wheels to simulate a floating axle. Such systems shift fluid back and forth to extend and simultaneously retract opposed hydraulic cylinders at the front or rear to level the vehicle. Although such hydraulic suspension systems generally provide for a ride with improved leveling, such systems may suffer from lack of responsiveness or overcorrection in certain situations. Therefore, such vehicles may are subject to tipping over, especially when working on a hillside or when a hole is encountered by one of the wheels.
A system is needed that provides for large coverage to maintain stability when the center of gravity of the vehicle is over the supported area formed by the support points of the vehicle. Under various operating conditions with a floating axle, the suspension system has support points that change. An improved hydraulic suspension system would provide stable correction with a stability area that overlaps as it shifts and is not vulnerable to tipping over. Such a suspension system should also have the advantages of a floating axle to maintain a level operating orientation. Such a system should also be simple and reliable. The present invention addresses these as well as other problems associated with hydraulic suspension systems for vehicles operating on slopes.